This is the DuraTrax Onyx 6-Cell, 7.2V, 5000mAh NiMH Stick Battery Pack, with a Tamiya Connector. Onyx packs are "true" rated, so they deliver on their performance promises and you get the capacity you paid for. Onyx stands for cells that can stand up to repeated run-and-recharge cycles on the same day for a pack that will last and last.